Method, control device, and system for determining a profile depth of a profile of a tyre

Abstract

A method for determining a tread depth of a tread of a tire during operation of a vehicle comprising the tire, a controller for a vehicle for determining a tread depth of a tread of a tire of the vehicle, and a system for a vehicle, comprising such a controller and at least one electronic wheel unit, wherein there is provision to determine the tread depth based on a determined instantaneous dynamic wheel radius of a wheel, comprising the tire, of the vehicle and a determined instantaneous dynamic inside radius of the tire are disclosed. To improve the accuracy of determination of the tread depth a correction variable predetermined for the type of tire is taken into consideration, which correction variable characterizes the relationship between a change in the tread depth, and a change resulting therefrom in the difference between the dynamic wheel radius and the dynamic inside radius.

The invention claimed is: 
     
       1. A method for determining a tread depth of a tread of a tire during operation of a vehicle comprising the tire, comprising:
 determining an instantaneous rotational speed of a wheel, comprising the tire, of the vehicle based on data determined by at least one first sensor, 
 determining an instantaneous speed of the vehicle based on data determined by at least one second sensor different from the at least one first sensor, 
 determining an instantaneous dynamic wheel radius of the wheel comprising the tire, based on the determined instantaneous rotational speed and the determined instantaneous speed of the vehicle, 
 determining at least one first operating parameter of the tire, selected from the group consisting of an instantaneous tire temperature, an instantaneous tire pressure and an instantaneous tire load, 
 determining an instantaneous dynamic inside radius of the wheel based on the at least one determined first operating parameter, wherein the inside radius of the wheel is the distance between the wheel center and the tire-side start of the tread, 
 determining a tread depth of the tread of the tire based on the determined instantaneous dynamic wheel radius and the determined instantaneous dynamic inside radius, 
 
       wherein the tread depth is determined based at least in part on a correction variable predetermined for the type of tire, wherein the correction variable characterizes the relationship between a change in the tread depth and a change resulting therefrom in the difference between the dynamic wheel radius and the dynamic inside radius. 
     
     
       2. The method as claimed in  claim 1 , wherein a correction constant characteristic to the type of tire is used as the correction variable, which correction constant represents the relationship between the change in the tread depth and the change resulting therefrom in the difference between the dynamic wheel radius and the dynamic inside radius. 
     
     
       3. The method as claimed in  claim 1 , wherein a correction function, characteristic to the type of tire, configured to map a difference between the dynamic wheel radius and the dynamic inside radius onto a change in the tread depth is used as the correction variable. 
     
     
       4. The method as claimed in  claim 3 , wherein the function value of the correction function additionally depends on at least one function parameter, selected from the group consisting of the speed of the vehicle, the tire temperature, the tire pressure and the tire load. 
     
     
       5. The method as claimed in  claim 1 , wherein the tread depth is determined utilizing at least one characteristic curve stored in a memory device. 
     
     
       6. The method as claimed in  claim 1 , wherein at least one second operating parameter is additionally determined, the second operating parameter being selected from the group consisting of an instantaneous acceleration of the vehicle, an instantaneous yaw rate of the vehicle, an instantaneous steering angle, an instantaneous torque of a drive motor of the vehicle and an operating state of a braking device of the vehicle, and wherein the tread depth is additionally determined depending on the at least one determined second operating parameter. 
     
     
       7. The method as claimed in  claim 1 , wherein the at least one first sensor is configured as a rotational speed sensor. 
     
     
       8. The method as claimed in  claim 1 , wherein the at least one second sensor is selected from the group consisting of a satellite-assisted position determination sensor, a radar sensor, a lidar sensor, an ultrasound sensor and an optical camera. 
     
     
       9. The method as claimed in  claim 1 , wherein the instantaneous dynamic inside radius is additionally determined based on the determined instantaneous speed of the vehicle or additionally determined based on the type of tire or an age of the tire. 
     
     
       10. The method as claimed in  claim 1 , wherein the instantaneous dynamic inside radius is determined utilizing at least one characteristic curve stored in a memory device. 
     
     
       11. A computer program product comprising a program code that, when executed on a data processing device, performs a method as claimed in  claim 1 . 
     
     
       12. A controller for a vehicle for determining a tread depth of a tread of a tire of the vehicle, comprising:
 a reception device, configured to receive an instantaneous rotational speed of a wheel, comprising the tire, of the vehicle, an instantaneous speed of the vehicle and at least one first operating parameter of the tire, selected from the group consisting of an instantaneous tire temperature, an instantaneous tire pressure and an instantaneous tire load, 
 a first determination device, configured to determine an instantaneous dynamic wheel radius of the wheel comprising the tire based on the received instantaneous rotational speed and the received instantaneous speed of the vehicle, 
 a second determination device, configured to determine an instantaneous dynamic inside radius of the wheel based on the at least one received first operating parameter, wherein the inside radius of the wheel is the distance between the wheel center and the tire-side start of the tread, and 
 a third determination device, configured to determine a tread depth of the tread of the tire based on the determined instantaneous dynamic wheel radius and the determined instantaneous dynamic inside radius, 
 
       wherein the third determination device is configured to determine the tread depth based at least in part on a correction variable predetermined for the type of tire, wherein the correction variable characterizes the relationship between a change in the tread depth and a change resulting therefrom in the difference between the dynamic wheel radius and the dynamic inside radius. 
     
     
       13. A system for a vehicle for determining a tread depth of a tread of a tire of the vehicle, comprising a controller as claimed in  claim 12  and at least one electronic wheel unit, wherein the at least one electronic wheel unit is able to be arranged in the tire and comprises at least one sensor selected from the group consisting of a temperature sensor, a pressure sensor, an acceleration sensor and a deformation sensor.